Lock has evolved for hundred years, aiming at enhancing its antitheft function. Even locks with electronic devices, such as mechanisms for finger print and voice recognition, are invented, they are expensive to manufacture and maintain. Therefore, mechanical locks are still the main stream.
The lock barrel of a lock has a set of pins and associated recoil springs. A key to the lock can switch the positions of the pins, achieving the purpose of opening the lock. To open the lock without a key, a slim, elongated tool is inserted into the key channel in the lock barrel for activating the pins.
In other words, a lock barrel is the core mechanism of a lock and where an antitheft innovation should be applied to. One effective way of enhancing the antitheft function of a lock barrel is using a non-straight key channel, therefore making the intrusion of an illegal tool difficult. However, it is difficult to manufacture such a lock, since the key must be foldable; special materials should be used to make the key.
There is another way to enhance the antitheft function. Minimizing the key channel of a lock barrel so that external objects other than the key cannot be inserted into is an example. However, the production of this kind of key barrels concerns the building of molds of much better precision, which is expensive. Further, the key associated with a lock barrel of small key channel is usually structurally weak.